A thin, tube-like instrument used to examine the tissues and lymph nodes in the area between the lungs. These tissues include the heart and its large blood vessels, trachea, esophagus, and bronchi. The mediastinoscope has a light and a lens for viewing and may also have a tool to remove tissue. It is inserted into the chest through a cut above the breastbone.

Mediastinoscopy. A mediastinoscope is inserted into the chest through an
incision above the breastbone to look for abnormal areas between the
lungs. A mediastinoscope is a thin, tube-like instrument with a light
and a lens for viewing. It may also have a cutting tool. Tissue samples
may be taken from lymph nodes on the right side of the chest and checked
under a microscope for signs of cancer. In an anterior mediastinotomy
(Chamberlain procedure), the incision is made beside the breastbone to
remove tissue samples from the lymph nodes on the left side of the
chest.